The invention relates to techniques for sensing the relative position of an inductive sensing element along a specified direction or coordinate, and more particularly to techniques of this type employing an array of conductive elements sequentially arranged in parallel along such coordinate and disposed in magnetic coupling relation to the sensing element.
In existing facilities of this type, the successive conductors are excited sequentially with spaced, substantially rectangular current pulses to induce an impulse-type voltage resonse in the sensing element. Such voltage response exhibits a plurality of successive amplitude spikes, corresponding to the number of conductors disposed along the test area, and the amplitude distribution of the spikes is detected as an indication of the position of the sensing element with respect to a reference point of the test area, such reference point arbitrarily corresponding to the start of the cycle of excitation of the conductor array; in general, the position of the sensing element is correlated with the time of occurrence of the largest amplitude spike of the induced voltage response.
Such arrangements are complicated and inaccurate, and do not permit of ready interpolation of position between the successive conductors unless an inordinate number of such conductors are distributed in a relatively small area to be measured.